It’s not an attribute, but it is an Object property that is available to Mod scripts. With that being said, if you want a token to always come out at the same size, then set the size you want for the token, then make sure the last step you do is to save that token as the default for the associated character sheet. Any changes that are made after saving the default token will not be saved and happen the next time you pull out the token. Also make sure that your maps are set to the same grid size, as grid with different sizes will affect the size of tokens that are pulled out.